1. Field of the Invention
This invention relates to improved apparatus and a process for the pyrolysis of dehydrated waste solids concentrates. More particularly, it relates to improved apparatus and a process for the thermal decomposition of organic material comprising essentially the following process steps: admixing oil to the waste solids, heat evaporating off substantially all the water content of the organic material, de-oiling the resulting, dehydrated organic material, and pyrolizing or destructively distilling this material to produce distillable lower molecular weight organic compounds, char and ash.
2. Description of the Prior Art
The efficient economic disposal of waste solids concentrates is a recognized problem. Particularly in recent years because of increased emphasis on environmental impact problems associated with air and water pollution, land contamination and disposal problems, the necessity of developing disposal apparatus and processes which are economically efficient and relatively pollution free has become increasingly important. Furthermore, such processes should also obtain valuable by-products, or alternatively, recycle materials through the process to improve their efficiency.
The prior art processes, however, have not solved these pressing problems but rather usually involve some form of settling, aeration, chemical treatment or thermal decomposition of the organic material. Each of these processes produce unwanted discharges into the atmosphere or the earth or are very time consuming. For example, in the customary prior art process for raw sewage it is first treated by settling, aeration, and chemicals to generate a stream of water sufficiently clean to be discharged into a river or stream with a residue of sewage sludge discharge into a closed tank called a digester. The digester must be of sufficient volume to permit a dwell-time of 30 days or longer. Heating means such as hot water coils are provided in the digester, and the sludge is maintained at an elevated temperature to provide anaerobic bacterial digestion of the organic constituents which break down the solids in part into gaseous material. The gaseous material may have a substantial content of methane and thus be drawn off continuously to be burned as a fuel for heating the water circulated through the digester coils. Sewage solids in a stream which may have a water content of about 95 percent are drawn off from the digester and spread out in large drying beds for final evaporative drying. The resulting dry solids may be incinerated or disposed of to farms for fertilizer and other possible uses.
If instead of the evaporative drying process the organic waste are burned or thermally decomposed within a furnace and oxygen or air be used, great volumes of gases may be produced which are then discharged as an air stream into the atmosphere. Additionally, solid particulate matter may be discharged into the atmosphere as suspended particles within the air stream.
Further the prior art processes generally suffer from an inability to utilize the products or the energy produced within the process to efficiently carry out the process and reduce the energy required for the process.
It is therefore an object of this invention to operate the apparatus and processes of this invention so that the energy requirements of the process are kept to a minimum while at least a portion thereof is produced by the process itself.
It is a further object of this invention to operate the apparatus and processes of this invention so that the end products of the process are held to a minimum but produced in a useful form.
It is a further object of this invention to operate the apparatus and processes to be environmentally efficient and produce a negligible discharge of pollutants into the atmosphere or environment in general.
It is a further object of this invention to operate the apparatus and process of this invention in a manner which avoids the necessity of obtaining special equipment subject to contamination and deterioration by the process conditions and the products thereof.